Will I be held responsible for my fiances tax debt after we get married?

You cannot be held responsible for any debt of your fiance even if you marry him.

Generally speaking, if you did not incur the debt, you will not acquire responsibility or liability for the debt simply by marrying. However, in addition to that debt continuing to affect him, if you file taxes jointly with a spouse who owes taxes, the government will attach refunds made on a joint filing. Thus you may find that some of the advantages of filing jointly will not be available to you until the debt is resolved. Your question does not provide enough detail to know whether his debt for business related taxes may be dischargeable in bankruptcy. While bankruptcy will be a knock on his credit score, outstanding tax liabilities will likely affect that as well. If this is of interest to him, he will want to consult with an experience bankruptcy attorney to see if the debt he owes is dischargeable.

You cannot be held personally liable for tax debt that belongs to someone else unless that tax debt is for a year in which you filed married/joint with that person. Therefore, you will never be liable for the taxes your finacee incurred prior to your getting married. However, if you file jointly with your soon-to-be-spouse and he/she still owes back taxes, you will lose your tax refund. You may want to file married/separate until he/she clears up the tax situation. I suggest you consult with a tax lawyer to advise you on this.